J. Waters was a strong early advocate of the project, provided invaluable scientific advice throughout the project, and gave feedback on the manuscript. A. Jost provided valuable feedback on data presentation, and G. Campbell helped with data input. N. Shaner and J. Goedhart provided advice on data presentation, and also are members of the FPbase scientific advisory group, along with T. Hughes and A. Palmer. The interactive chart on the FPbase website was modified from an earlier collaboration with K. Thorn. Salary support for TL is provided by the Departments of Cell Biology, Systems Biology, and BCMP at Harvard Medical School.